He can definitely do dark roles, but I'm not sure if I'd want him as a main villain. Guess it would depend on the villain in question and what Nolan's vision for that villain is, though. But I'd prefer to see him in a smaller role. I do think he deserves to be in a Batman movie, though, after the way WB teased him with the Joker in '89 and then with Riddler in Forever.